GESTATIONAL AGE AT DELIVERY AND LAXITY /
HYPOTONIA IN DOWNS: IS THERE A LINK? AN EPIDEMIOLOGICAL EXTENSION OF TWO
SEPARATE INVESTIGATIONS ON A SERIES OF 510 SUBJECTS.
Renato Cocchi, neurologist and medical
psychologist.
Summary.
Derived from the same consecutive series
of 510 Down Ss, two subsamples were sorted, the first of 142 Ss with laxity /
hypotonia and the second of 68 Ss with prematurity (gestational age at
delivery: 32-36 weeks). The whole data have been now crossed to investigate the
role of gestational age at delivery in the onset of laxity / hypotonia. No
gender prevalence was found as for the gestational age at delivery and the
presence or absence of laxity / hypotonia. Statistically significant male
prevalence (0.02) was found as for the premature gestational age and laxity /
hypotonia. Premature gestational age could be a worsening factor for the onset
of laxity / hypotonia in Down syndrome Ss.
Key words: Down syndrome; prematurity,
laxity / hypotonia; link; stress; gender, prevalence.
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Following my previous investigations on
ligamentous laxity and hypotonicity (Cocchi 2003) and on prematurity and low
birth weight in Downs (Cocchi, 2004) I decided to cross the data of these two,
to search a possible link between prematuryty and laxity / hypotonia in this
population.
The starting point of this research came
from the same consecutive series of 510 Down persons, selected by the exclusion
of autisic and other PPD subjects.
Materials and methods.
This investigation used my clinical cards
referring to a consecutive series of home reared and home living Italian Downs
as seen in outpatients' clinic by myself since 1979 to 1993. Psychotic
subjects' cards were excluded.
During their 1st consultation I recorded the
gestational week at delivery as I checked on discharge cards of the obstetrics
department or as the parents told me. During the first consultation I noted the
presence of the absence of ligamentous laxity /hypotonicity.
From all cards I collected:
- the gender;
- the chromosomal diagnosis;
- the age at 1st consultation;
- the gestational week at delivery;
- ligamentous laxity and/or muscle hypotonicity
(termed also, laxity / hypotonia).
I statistically processed data by gender,
chromosomal diagnoses, prematurity, laxity / hypotonia. I applied Chi Square
Test, when suitable.
Results.
The results are detailed in tables 1-7.
Tab 1: Epidemiological data of the whole
series.
.
|
|
No. of Ss |
% |
|
|
510 |
100.00 |
|
Males |
292 |
57.25 |
|
Females |
218 |
42.57 |
|
M/F ratio |
133.94 |
|
|
|
|
|
|
Chromosomal diagnoses |
|
|
|
Standard trisomy 21 |
461 |
90.39 |
|
Mosaicisms |
16 |
3.14 |
|
Translocations |
16 |
3.14 |
|
Unknown, only clinical diagnosis |
17 |
3.33 |
|
|
|
|
|
Age at 1st consultation (months) |
|
|
|
Range |
6-510 |
|
|
Average +/- SD |
71.37 +/- 69.71 |
|
As we may see in the table 1, the M/F ratio
appears poorly different (133 vs 135) from what we know for Italian newborn and
alive Down children (Camera and Mastroiacovo,1984). Even the distribution of
the chromosomal diagnosis, meets the ranges of variability for Italian and
international samples (Camera e Mastroiacovo,1984; Hook, 1983; Hook, Cross and
Schreinemachers, 1983).
For these reasons, we may think the sample
here investigated as representative of at least the Italian population of
Downs.
Tab. 2: Distribution of the prevalence of the symptom "laxity /
hypotonia" according to gender, chromosomal diagnosis and age at first
consultation.
|
|
Ss no. |
% |
|
The whole sample |
510 |
100.00 |
|
Not investigated |
9 |
1.76 |
|
Symptom presence |
142 |
27.84 |
|
|
||
|
Symptom presence |
142 |
100.00 |
|
Males |
79 |
55.63 |
|
Females |
63 |
44.37 |
|
M/F ratio |
125.40 |
|
|
|
||
|
Chromosomal diagnosis |
|
|
|
Standard trisomy 21 |
130 |
91.55 |
|
Translocations |
6 |
4.22 |
|
Mosaicisms |
4 |
2.82 |
|
Only clinical diagnosis |
2 |
1.41 |
|
|
||
|
Age at first consultation |
|
|
|
Average +/- SD (months) |
35.98 +/- 35.33 |
|
|
Range (months) |
6-164 |
|
Tab. 3: Epidemiological data of the
subsample (68 Ss) with prematurity.
|
|
No. of Ss |
% |
|
Total subsample |
68 |
100.00 |
|
M |
53 |
77.94 |
|
F |
15 |
22.06 |
|
M/F ratio |
353.33 |
|
|
|
||
|
The whole sample |
510 Ss |
100.00 |
|
M |
292 |
57.25 |
|
F |
218 |
42.57 |
|
M/F ratio |
133.04 |
|
|
Chi Square for gender = 9.828 with 1 df and p = 0.002 |
||
|
|
||
|
Chromosomal diagnoses |
|
|
|
Standard trisomy 21 |
62 |
91.18 |
|
Mosaicisms |
1 |
1.47 |
|
Translocations |
3 |
4.41 |
|
Only clinical diagnosis |
2 |
2.94 |
|
|
||
|
The whole sample |
510 |
100.00 |
|
Standard trisomy 21 |
461 |
90.39 |
|
Mosaicisms |
16 |
3.14 |
|
Translocations |
16 |
3.14 |
|
Only clinical diagnosis |
17 |
3.33 |
|
Chi Square for chromosomal diagnoses = 0.895 with 3 df and p = 1.000 NS |
||
The tab. 3 shows a very interesting datum.
Males seem to have more easiness of premature births.
Tab 4.: Distribution of the weeks of
gestational age vs presence of laxity / hypotonia (severity graduated with +,
++, +++).
|
|
Presence of laxity / hypotonia |
Presence of laxity / hypotonia |
||
|
Week of gestation |
Females |
Males |
||
|
Age vs severity |
No. of Ss |
% |
No. of Ss |
% |
|
Not recorded vs + |
3 |
4.76 |
4 |
5.06 |
|
|
|
|||
|
32 vs + |
1 |
1.59 |
0 |
0.00 |
|
33 vs + |
1 |
1.59 |
1 |
1.27 |
|
35 vs + |
2 |
3.17 |
0 |
0.00 |
|
36 vs + |
0 |
0.00 |
4 |
5.06 |
|
|
Chi Square = 6.884 with 3 df and p = 0.99 NS |
|||
|
37 vs + |
2 |
3.17 |
8 |
10.12 |
|
38 vs + |
6 |
9.52 |
8 |
10.12 |
|
39 vs + |
1 |
1.59 |
2 |
2.53 |
|
40 vs + |
23 |
36.50 |
20 |
25.31 |
|
42 vs + |
1 |
1.59 |
1 |
1.27 |
|
|
Chi Square = 4.109 with 4 df and p = 0.391 NS |
|||
|
43 vs + |
1 |
1.59 |
1 |
1.27 |
|
|
|
|||
|
Not recorded vs ++ |
3 |
4.76 |
6 |
7.59 |
|
|
|
|||
|
34 vs ++ |
0 |
0.00 |
3 |
3.80 |
|
35 vs ++ |
0 |
0.00 |
2 |
2.53 |
|
36 vs ++ |
1 |
1.59 |
3 |
3.80 |
|
|
Chi Square = 1.343 with 2 df and p = 0.511 NS |
|||
|
37 vs ++ |
1 |
1.59 |
0 |
0.00 |
|
38 vs ++ |
1 |
1.59 |
3 |
3.80 |
|
39 vs ++ |
1 |
1.59 |
1 |
1.27 |
|
40 vs ++ |
12 |
19.04 |
7 |
8.86 |
|
41 vs ++ |
1 |
1.59 |
1 |
1.27 |
|
|
Chi Square = 2.774 with 4 df and p = 0.596 NS |
|||
|
|
|
|||
|
Not recorded vs +++ |
0 |
0.00 |
2 |
2.53 |
|
|
|
|||
|
36 vs +++ |
1 |
1.59 |
1 |
1.27 |
|
|
|
|||
|
40 vs +++ |
1 |
1.59 |
1 |
1.27 |
|
Totals |
63 |
100.00 |
79 |
100.00 |
No gender prevalence was found.
Tab 5 . Distribution of the weeks of
gestational age vs absence of laxity / hypotonia (-)
|
|
Absence of laxity / Hypotonia |
Absence of laxity / Hypotonia |
||
|
Week of gestation |
Females |
Males |
||
|
Age vs severity |
No. of Ss |
% |
No. of Ss |
% |
|
Not recorded vs - |
17 |
11.89 |
23 |
10.65 |
|
|
|
|||
|
32 vs - |
0 |
0.00 |
1 |
0.46 |
|
33 vs - |
0 |
0.00 |
1 |
0.46 |
|
34 vs - |
2 |
1.40 |
3 |
1.39 |
|
35 vs - |
0 |
0.00 |
3 |
1.39 |
|
36 vs - |
7 |
4.89 |
30 |
13.89 |
|
|
Chi Square = 2.519 with 4 df and p 0.641NS |
|||
|
37 vs - |
3 |
2.10 |
17 |
7.87 |
|
38 vs - |
.17 |
11.89 |
26 |
12.04 |
|
39 vs - |
10 |
6.99 |
9 |
4.17 |
|
40 vs - |
75 |
52.46 |
87 |
40.28 |
|
41 vs - |
5 |
3.49 |
7 |
3.24 |
|
42 vs - |
5 |
3.49 |
4 |
1.85 |
|
|
Chi Square = 8.507 with 5 df and p = 0.136 NS |
|||
|
43 vs - |
2 |
1.40 |
4 |
1.85 |
|
44 vs - |
0 |
0.00 |
1 |
0.46 |
|
|
Chi Square = 0.275 with 1 df and p 0.600 NS |
|||
|
Totals |
143 |
199.00 |
216 |
100.00 |
Nine Ss are lacking in the tab. 4-5 because
no information about both laxity / hypotonia and prematurity was reported.
No gender prevalence in every subsample, made
according to gestational age at delivery.
Tab. 6.: Comparison between Ss with premature
delivery with and without laxity / hypotonia.
|
|
Prematurity with laxity / hypotonia |
Prematurity without laxity / hypotonia |
||
|
Gestational week |
No.of Ss |
% |
No. of Ss |
% |
|
32 |
1 |
5.00 |
1 |
2.13 |
|
33 |
2 |
10.00 |
1 |
2.13 |
|
34 |
0 |
0.00 |
5 |
10.64 |
|
35 |
2 |
10.00 |
3 |
6.39 |
|
36 |
4 |
20.00 |
37 |
78.72 |
|
Totals |
9 |
100.00 |
47 |
100.00 |
|
|
Chi Square = 11.662 with 4 df and p = 0.02 |
|||
As for this subsample, premature gestational
age is statistically significant and a possible cofactor for the onset of
laxity / hypotonia.
Tab 7: Comparison between Ss with normal age
delivery with and without laxity / hypotonia.
|
|
Normal gastational age with laxity / hypotonia |
Normal gestational age without laxity / hypotonia |
||
|
Gestational week |
No.of Ss |
% |
No. of Ss |
% |
|
37 |
9 |
9.00 |
20 |
7.55 |
|
38 |
18 |
18.00 |
43 |
16.23 |
|
39 |
5 |
5.00 |
19 |
7.17 |
|
40 |
64 |
64.00 |
162 |
61.12 |
|
41 |
2 |
2.00 |
12 |
4.53 |
|
42 |
2 |
2.00 |
9 |
3.49 |
|
Totals |
100 |
100.00 |
265 |
100.00 |
|
|
Chi Square = 2.625 with 5 df and p = 0.921 NS |
|||
As for this subsample, normal age delivery does
not interfere with the onset of laxity / hypotonia.
Discussion.
Fewer words of discussion can be written on
this new research. This is the first one on this topic, at least for what I
found on Google and on Medline since 1960. This appears very strange because
the Down syndrome has greatly dedicated literature. Evidently, this is a topic
of poor interest.
The results gained here, besides the
prevalence of premature males already seen in the preceding research (Cocchi, 2004),
are only 1. Prematurity and laxity / hypotonia seem two independent phenomena
in Down syndrome; 2. Prematurity could be a worsening factor in Down subjects
with laxity / hypotonia.
References.
Camera G., Mastroiacovo
P.: Epidemiologia della sindrome di Down. In. Ce.Pi.M. (ed): Aspetti
epidemiologici, genetici, clinici, riabilitativi e sociali della sindrome di
Down. Ce.Pi.M., Genova 1984: 225-230.
Cocchi R. Ligamentous
laxity and hypotonicity in Downs. An epidemiological investigation on 510
subjects. 2003 <www.stress-cocchi.net/Downs34.htm>.
Cocchi R. Prematurity
and low birth weight in Downs. An epidemiological investigation on 510
subjects. July 2004, <www.stress-cocchi.net/Downs44.htm>.
Cocchi R. Which
relationship between tongue protrusion and joint laxity / hypotonia in Downs?
An epidemiological investigation on 452 subjects. 2004
<www.stress-cocchi.net/Downs43.htm>.
Hook, E. G Epidemiology
of Down syndrome. In, Pueschel, S. M. and Rynders, J. E. (eds.): Down Syndrome.
Advances in Biomedicine and the Behavioral Sciences. Cambridge: Ware
Press,1983.
Hook, E. B.; Cross, P.
K. and Schreinemachers, D. M. (1983). Chromosomal abnormality rates at
amniocentesis and in live-born infants. J.A.M.A. 1983, 249: 2034-2038,
First posted on Internet on June 30, 2004. Copyright by R. Cocchi, 2004.
Author's address: Dr
Renato COCCHI, via Rabbeno, 3
42100 Reggio Emilia
(Italy)
renatococchi@libero.it
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